Molecular Plant Pathology - Pathogen Profiles
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Colletotrichum: tales of forcible entry, stealth,
transient confinement and
breakout
Akinwunmi O. Latunde-Dada
Department of Plant Pathology, IACR-Rothamsted, Harpenden, Hertfordshire,
AL5 2JQ, UK
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| Taxonomy: |
Imperfect, anamorphic fungus (subdivision Deuteromycotina, form-class
Deuteromycetes, form-subclass Coelomycetidae, form-order Melanconiales,
form-family Melanconiaceae) with 39 'accepted' species [Sutton, B.C.
(1992) The genus Glomerella and its anamorph Colletotrichum.
In: Colletotrichum: Biology, Pathology and Control (Bailey, J.A.
and Leger, M.J., eds). Wallingford, UK: CAB International, pp. 1-26.]
which continue to be revised and clarified by molecular taxonomic
techniques. Species complexes and subspecific groups have been proposed.
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| Host range: |
Species of Colletotrichum
attack a large number of important tropical and sub-tropical crop species
and cause economically significant diseases of cereals, grain legumes,
vegetables, forage legumes, fruit crops and perennial crops. Tropical and
sub-tropical fruit production is significantly affected by postharvest
anthracnose. |
| Disease symptoms: |
Symptoms of the attack are commonly
known as anthracnose and comprise dark, sunken, lenticular necrotic
lesions containing the acervuli of the pathogen. |
| Key attractions: |
A model fungus for research on host
specificity, mycoherbicides, appressorial melanization, appressorial
function, quiescent infection, fungal lifestyles, intracellular
hemibiotrophy and the determinants of the switch from biotrophy to
necrotrophy among others. |
| Useful web site: |
http://www.uark.edu/depts/plant/
http://www.sorghumanthracnose.org/
http://www.iacr.bbsrc.ac.uk/ppi/staff/roc_rc.html |
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From transient confinement to breakout: light micrographs of
post-penetration events in leaf epidermal cells of four different host
plants inoculated with Colletotrichum destructivum, C. linicola
or C. truncatum. Bar = 10 µm.
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(a) Formation of an intracellular saccate infection
vesicle, with a long narrow neck emanating from a melanized appressorium,
in an epidermal cell of lentil (Lens culinaris) 24 h after inoculation
with C. truncatum.
(b) A fully developed multilobed vesicle of C.
destructivum confined transiently within an epidermal cell of cowpea (Vigna
unguiculata) 72 h after inoculation.
(c) Invasion of neighbouring cells by secondary
hyphae, developing 84 h after inoculation, from a multilobed vesicle of C.
truncatum that was initially confined within an epidermal cell of
broad bean (Vicia faba). Arrows indicate breakout points.
(d) Radiation of secondary hyphae from the distal ends of a multilobed
vesicle of C. linicola into leaf tissues of flax (Linum
usitatissimum), 96 h after inoculation. Arrows indicate points at
which the walls of the initially infected epidermal cell were bridged. |
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